For millions of children in the American education system, more venture money doesn’t necessarily translate to a better education. The U.S., which has seen over 75 percent of the edtech capital committed in the past five years, still trails behind the worldwide average in K-12 education scores.

Until recently, the majority of the startup community has been absent in discussions around education reform. Entrepreneurs and venture investors have largely ignored the K-12 market and made bigger bets on adult education startups instead — like professional edtech platform lynda.com, whose $186 million raised in January is the largest edtech financing seen in the past six years, according to CrunchBase data.

Now the results from edtech’s banner year are in, and it appears a revival in K-12 investing is underway.

In 2014, startups with a primary or secondary education focus accounted for nearly $400 million of the total $1.8 billion in venture capital committed, according to a report compiled by GSV Advisors. This is more than double 2013’s total.

“We’ve been doing education for 17 years, and there were probably ten years there where we were the only people who touched a K-12 company because everybody hated it. It was too hard and the procurement was awful,” says Deborah Quazzo, founder of GSV and member of the Chicago Board of Education.

The venture firms that did invest got burned. “If you look back 10 years, Kleiner and Accel put $225 million dollars into a company called Lightspan, and it finally sold for $50 million, which was lucky. It was just too early — teachers were not ready, schools were not wired, funding wasn’t available,” says Quazzo.

But today, devices are cheaper, students are more tech-savvy, and classrooms are better connected.

“Chromebooks are now less than $300 bucks, they cost what a textbook used to cost,” says Tom Vander Ark, edtech advocate and managing partner at Learn Capital. “If you make good use of open content, you can actually save money by shifting to a higher access environment,” Vander Ark points out.

School districts have already started experimenting with equal access solutions, but a handful of failures have proven that implementing technology at scale is not an easy task.

In 2013, LA Unified School District agreed to funnel $1.3 billion into a district-wide initiative that would give each student an iPad. The program was plagued by problems from the start — teachers were not prepared, Internet connection was spotty, and students quickly bypassed security blockers. LAUSD finally suspended the program in December in the midst of an FBI investigation into the bidding process that won Pearson and Apple the district-wide contract.

“I’m less of an enthusiast about ‘let’s just get every kid an iPad and we’ll figure it out,'” says Mitch Kapor, founder of social impact fund Kapor Capital. “The idea that you could just throw technology at a problem and raise up kids from low-income backgrounds? It was predictable that it wasn’t going to work.”

The failure of these experiments have led some to conclude that edtech isn’t leveling the playing field at all — in fact, it’s making it worse. Researchers are drawing on the idea that early advantages tend to multiply over time to posit that a tablet in the hands of a disadvantaged student is not the same as a tablet in the hands of his privileged counterpart.

“There’s a heightened disappointment cycle about new technology that plays out in general in our ecosystem, and we’re seeing that play out to some extent in edtech,” says Kapor. “When new technology in the classroom starts happening, some people get very excited and think of it as a panacea. It attracts very high amounts of money, it raises expectations, and those expectations aren’t met.”

The latest batch of venture-backed edtech companies are making progress. According to Kapor, several of Kapor Capital‘s startups have already crossed the million student threshold, with some startups penetrating 30-40% of all public schools. The two-year-old startup Newsela, which tailors news-centric content to individual reading levels, has already registered teachers in half the schools in the country.

“If you look at the K-12 school population this year, for the first time students of color form the majority — we’ve reached that tipping point already,” says Kapor. “So we are looking at companies that are going into K-12 classrooms and public schools that are set on reducing the achievement gap.”

But how do you measure which startups are successful at reducing the achievement gap? Kara Chesal is working on a solution at the NYC Department of Education’s InnovateNYC Schools program.

“Impact is really hard to measure with things that are changing over time. Think about the medical industry — if you give someone a drug, you know that you’re giving them the same drug more or less — you’re able to control what the dosage is, how they’re using it, when they’re using it, and you’re confident that over time it’s not changing. When we look at educational technology products, it’s a lot more difficult to make sure that whatever that intervention or product is looks identical across all those different classrooms,” says Chesal.

In 2014 the Gates Foundation backed InnovateNYC so it could work with Johns Hopkins University to figure out a better way to measure the efficacy of new technology in the classroom. One of the companies that InnovateNYC is working with, Kinvolved, is an attendance improvement solution that targets students from disadvantaged backgrounds who are chronically absent from school.

“To close the achievement gap we have to look for support from multiple perspectives and lenses, so changing pedagogy, changing the leadership, making sure students are independent,” says Chesal. “Technology is one lever in that, it’s not necessarily a silver bullet, but it can be an enabler.”

Chesal hopes that Innovate NYC will provide teachers with a way to track down and compare the latest classroom tech products instead of relying on word of mouth. It’s especially valuable in school districts like New York City, where principals maintain control of each school’s budget.

“Then there’s the whole question of city-wide or district-wide adoption of things — it’s the same as selling in the enterprise and trying to get full adoption,” says Kapor. “That’s where the challenge is gonna be for edtech, and that’s going to require some system change.”

Changing the system won’t happen at the blazing startup speed Silicon Valley is used to, but it’s off to a good start.

“There are all kinds of obstacles, whether it’s politics or money or whatever, but I am very optimistic,” says Quazzo. “And by the way, the solution is not simply technology either, it’s a million things, it’s the Jim Collins’ 20 million mile march. But you start with early childhood and you use technology as an accelerant, which I totally believe it is.”